So you can have your very own transport ship, and you can fill it with all the nasty cargo you like, but have to constantly worry about refueling and not sinking it (owning a server).

You can also ask someone to man that ship, but he's going to transport other people as well, so he'll let you have your own cargo truck on board his ship to pack it with whatever you like. You can have any truck brand, and you don't need to worry about the ship sinking anymore, but you still have to worry about the truck breaking down, and there will be other people onboard, driving around their own trucks, also you'll have no idea how big the ship is, and it can limit you even though you know your truck very well (having a VM).

Finally, you can have someone man the ship, and you get your own little box onboard it. You don't need to worry about sinking, fueling and machinery in general, and your box is much easier to onboard than a full-sized truck, but you're also confined to the box,
the ship will be packed full with other people's boxes and you'll have no idea how big the ship is (having containers).